Grandmaster of the Six Samurai [STON-EN000] Secret Rare Duel This explains why the goblins

This explains why the goblins remain unaffected

The ATK and DEF of a monster that destroys this monster as a result of battle is decreased by 500 points

0 Card type: Digimon Rarity: Secret Rare Digi type: Demon Lord/Seven Great Demon Lords Play Cost: 12 Form: Mega Attribute: Virus Digivolve Cost: 4 Digivolve Cost Level: 5 While you have 10 or more cards in your trash， your [Impmon] can digivolve into this card in your hand for a memory cost of 4， ignoring this card's digivolution requirements

while a monster is equipped to it by this effect

Grandmaster of the Six Samurai [STON-EN000] Secret Rare Duel This explains why the goblinsSet: Strike of Neos Card type: Effect Monster Rarity: Secret Rare Attack: 2100 Defense: 800 You can only have 1 "Grandmaster of the Six Samurai" monster on your side of the field. While you control a face up "Six Samurai" monster, you can Special Summon this card from your hand. When this card is destroyed by your opponent's card effect, add 1 "Six Samurai" monster from your Graveyard to your hand.